DE2142161A1 - Process for the production of flexible polyurethane foams - Google Patents

Description

_o,. . Dr. Mlchaet Hann

£ 14 / I 0 I Patent Attorney

635 Bad Nauheim

Burgailee f2b Telephone (060 32) 62 3?

August 20, 1971 H / EW (365)

The Dow Chemical Company, Midland, Michigan, USA

PROCESS FOR MANUFACTURING FLEXIBLE POLYURETHANE FOAMS

The invention relates to flexible polyurethane foams and a method for their production.

Flexible polyurethane foams are widely known in the art. Particularly important are the "cold-curing" Foams are called flexible polyurethane foams that have their final properties without one Obtain post-curing at elevated temperature. For the production of satisfactory cold-curing foams from polyether polyols a mixture of a polymeric isocyanate and a diisocyanate is usually used.

It is known that those made of a polyether polyol and Cold-curing foams produced from a diisocyanate are very difficult to process and, moreover, that they are are not as elastic as the foams made with polymeric isocyanates. With the use of polymer isocyanates, however, is associated with a significant deterioration in strength properties. Therefore had to improve the strength properties of the flexible cold-curing polyurethane foams, the Sehaura

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preparations an agent, for example ρ, ρ'-methylene-bis- (ortho-chloroaniline) can be added. However, substances of this type are poisonous and difficult to handle. Besides one ascribes them carzenogenic properties.

It has now surprisingly been found that you can get out an ester-modified polyether polyol and a polyisocyanate even without additional substances, such as ρ, ρ'-methyienbis (ortho-chloroaniline) can produce cold-setting foams with good physical properties.

It was also found that polyurethane foams made from an ester-containing polyether polyol in comparison to flexible polyurethane foams made from polyether polyols in at least one, more often in several of their physical Properties show an improvement, for example in their tensile strength, their tear resistance, their Elongation and its load-bearing capacity.

The ester-modified ones used according to the invention Polyether polyols have the general formula

OO

A - o / c - Z - ^ CO 4CH - CH - O) ^ ₁₅ - hJ _x

RR

in the A the remainder of an initiator or an output compound having 2 to 4 active hydrogen atoms and an active hydrogen equivalent weight of 400 to 2500, Z the remainder of an internal anhydride of a saturated one or unsaturated acyclic aliphatica polycarboxylic acids of a saturated or unsaturated «cyclic aliphatic polycarboxylic acid, an aromatic pr-iycarboxylic acid, of a halogenated descendant an as; he eats

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-3-, 2Η2161

Acids or a mixture of these acids, one of the two R hydrogen, the other K hydrogen, one Alkyl radical with 1 to 20 carbon atoms, a halomethyl radical, denote a phenyl radical / a phenoxymethyl radical or an alkoxymethyl radical and in the m a mean value from 1.0 to 2.0, η has a value from 1 to 5, χ has a value 2 to 4 and y has a value 1 or 2.

The ester-modified ones used according to the invention are prepared Polyether polyols by using an initiator or an output compound with 2 to 4 active hydrogen atoms with a polycarboxylic anhydride and a vicinal alkylene oxide or a substituted vicinal alkylene oxide implements. The reaction is generally carried out either for a time from 4 to 40, preferably from 6 up to 24 hours, at a temperature from 50 to 150 ° C., preferably from 80 to 120 ° C., in the absence of a catalyst or for a time of 3 to 24, preferably 4 to 8 hours at a temperature of 40 to 100 ° C., in the presence a basic catalyst such as an alkali hydroxide such as sodium hydroxide or potassium hydroxide, or one tertiary amine, such as triethylamine or trimethylamine, and then isolates the desired ester-modified polyether polyol.

Another process for preparing the ester-modified polyether polyols according to the invention is that the initiator or the starting compound with the polycarboxylic acid anhydride for a time of 1 to 4 hours, preferably 2 to 3 hours, at a temperature of 50 to 150 ° C , preferably at a temperature of 80 to 120 ° C ₅ and the vicinal alkylene oxide then slowly zuglbtj in the course of 1 to 24 hours in the absence of its catalyst, wherein

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the temperature is kept within the specified range during this time. In the presence of a basic catalyst the reaction is complete in 1 to 8 hours.

In general, the implementation is carried out in both processes in the absence of a catalyst. However, it is preferred in certain cases, for example when that alkylene oxide used an olefin oxide with more than three slowly reacting carbon atoms is to carry out the reaction in the presence of a basic catalyst.

In the first of the processes described above, the polycarboxylic anhydride is used in an amount of 0.3 to 5 mol to an active hydrogen atom contained in the initiator and the vicinal alkylene oxide in an amount of 1.5 to 15 moles to one mole of the anhydride used. Here, a molecule of the anhydride reacts with an active hydrogen atom of the initiator and then an average of 1.0 to 2.0 moles, usually 1.5 to 2.0 moles, of the alkylene oxide the carboxyl group generated by the reaction of the anhydride with the active hydrogen. If you have more than If one mole of anhydride is used for an "active hydrogen" atom, each active hydrogen atom reacts with 1 mole Anhydride and any resulting carboxyl group averaging about 1.0 to about 2.0 moles, usually 1.5 to 2.0 moles of alkylene oxide, while the remainder of the anhydride and alkylene oxide are the same Way and in the same sequence reacts with the ester-modified polyol formed and another ester-modified polyol forms. The excess alkylene oxide is then removed in a suitable manner a known method such as evaporation under reduced pressure or purging with inert gas.

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In the second process, the individual process stages carried out independently of one another, i.e. the anhydride is added to the initiator and sets the after completion of the implementation Alkylene oxide slowly. You can then place more as you wish Amounts of the acid anhydride and further adds alkylene oxide, until you get the product you want.

From the description of the two processes it is easy to see draw the conclusion that the first one before the second Gives preference.

Compounds are suitable as initiators or starting materials with 2 to 4 active hydrogen atoms, for example the Polypxyalkylene compounds from the reaction of a diol such as Propylene glycol, ethylene glycol, neopentyl glycol, dibronmeopentyl glycol, Butylene glycol or 1,6-hexanedipl, or one Triols, such as glycerine, trimethylolpropane or 1,2,6-hexanetriol, or a compound containing four active hydrogen atoms, such as pentaerythritol, diglycerol, ethylenediamine or aminoethylethanolamine, or a mixture of the above Compounds with a vicinal alkylene oxide, for example ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, an epihalohydrin or epibromohydrin, or a mixture of the compounds mentioned. The term "vicinal alkylene oxide" also includes monoglycidyl ethers, including aromatic glyeidyl ethers, such as cresyl glycidyl ether or phenyl glycidyl ethers and aliphatic glycidyl ethers such as butyl glycidyl ether or propyl glycidyl ether.

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For the reaction with the active hydrogen containing compound the vicinal alkylene oxide is used in such an amount that the obtained as starting material or initiator Polyoxyalkylene compound based on active hydrogen Equivalent weight from 400 to 2500, preferably from 600 bit 2000, has.

As suitable alkylene oxides, which together with the acid anhydride with the initiators or starting materials described to the novel ester-containing polyether polyols according to the invention can be implemented are the vicinal alkylene oxides, such as ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide; Epihalohydrins, such as epichlorohydrin, epibromohydrin or epiiodohydrin; Monoglycidyl ethers, including aliphatic glycidyl ethers, for example butyl glycidyl ether or propyl glycidyl ether and aromatic glycidyl ethers, for example phenyl glycidyl ether or cresyl glycidyl ether, and mixtures called dieter connections.

As internal anhydrides suitable for the purposes of the invention of polycarboxylic acids are saturated acyclic aliphatic anhydrides, such as succinic anhydride and glutaric anhydride or adipic anhydride; unsaturated acyclic aliphatic Anhydrides such as maleic anhydride, itaconic anhydride or citraconic anhydride; saturated and unsaturated cyclic aliphatic anhydrides such as 1-4 cyclohexanedicarboxylic acid anhydride or cis-4-cyclohexene-1,2-dicarboxylic acid anhydride; aromatic anhydrides such as phthalic anhydride, naphthalic anhydride, Hemimellitic anhydride, prehnitic anhydride, diphenic anhydride or trimellitic anhydride and halogen-containing dicarboxylic anhydrides, such as chlorendic acid anhydride, tetra

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. .chlprphthalic anhydride or tetrabromophthalic anhydride called. Mixtures of the abovementioned internal anhydrides can also be used.

The polyisocyanates used to produce the polyurethane foams according to the invention can be any organic polyisocyanates which have two or more NGO groups in the molecule, but do not contain any other substituents with the hydroxyl groups of the ester-containing polyether polyol be able to react. Suitable polyisocyanates of this type are, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, the hexamethylene diisocyanate, the p, p'-diphenylmethane diisocyanate, the dianisidine diisocyanate, the Polymethylene polyphenyl isocyanate and mixtures of several of these polyisocyanates.

Polyurethane foams can be any of the known ones Process, for example, according to the one-shot process ("oneshot"), a one-step process, or according to the "prepolymer" process or the "S a i-prepolymer" process, both two-stage processes, produce. These procedures are detailed in Chapter VII, Section III and Chapter VIII, Section III of Part II of the book "Polyurethanes: Chemistry and Technology" by Saunders and Frisch (Interscience, 1964) described.

In addition to the reactive components polyol and polyisocyanate, they are used in the production of polyurethane acids other substances used are propellants, catalysts and cell regulators.

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As catalysts promoting urethane formation, the Foam preparation, for example, tertiary amines added are ,, Examples are tetramethylbutanediamine, triethylenedianiine and called N-ethylmorpholine.

In addition to those mentioned, other catalysts can be used in the production of polyurethane foams, for example, lead (II) naphthenate, zinc naphthenate, aluminum distearate, Aluminum tristearate, lead (II) stearate, basic lead (II) stearate, Tin (II) octoate, tin (II) oleate, dibutyltin dilaurate, Aluminum monostearate, zinc stearate, cadmium stearate, Silver acetate, lead (II) pelargonate and mixtures of these compounds use.

As a cell regulator, i.e. as a means for the formation of the cell structure promote during foaming, silicone fluids are normally used. Also polyoxypropylene glycols with a Molecular weights from about 2000 to about 4000 are suitable for this purpose.

In addition to those mentioned, other substances can also be added to the polyurethane foam preparation, for example fillers medium or fire retardant.

For example, barium sulfate, calcium carbonate and mixtures thereof are suitable as fillers.

If you want to produce polyurethane foams with fire-retardant properties, you should use the foam preparation as fire-retardant Connections to. As such, phosphorus-containing compounds, for example tricresyl phosphate, are halogenated Phosphates, for example tris (dichloropropyl) phosphate or tris (2,3 = dibromopropyl) phosphate; halogenated phosphates, for example Bis (3-bromopropyl) -3-bromopropane-phosphonate;

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- 9 - 2H2161

halogenated glycols, for example dibromoneopentyl glycol, inorganic salts, for example magnesium ammonium phosphate, Ammonium bromide and calcium phosphate as well as any Geraische of these compounds mentioned.

The following examples illustrate the invention in greater detail.

example 1

A. Prepare an ester-containing polyether polyol as follows here that one mole of CP 4701, a commercially available polyoxypropylenetriol made with glycerine as initiator, which contains ethylene oxide grafted on in the end position and has a hydroxyl equivalent weight of about 1566 and 3.1 mol Maleic anhydride in a reaction vessel containing a stirring device, means for temperature control, a nitrogen inlet port and means for evacuation is, the air is removed by applying a vacuum, after releasing the vacuum with nitrogen 15 moles of ethylene oxide is added, heated to 120 ° C and the reaction mixture is kept at this temperature until the acid number falls below 1, i.e. for about 24 hours. The volatiles are removed by evaporation under reduced pressure and filtered the product. It has an OH content of 0.94% and an acid number of 0.74.

B. An elastic, cold-curing polyurethane foam is produced from part of the product obtained according to A. from the fact that it can be thoroughly treated with the substances mentioned in the recipe in Table I, aμsgenoramen the isocyanate mixes, the isocyanate is then incorporated into the mixture, the entire mixture is poured into an open mold and it goes into it leaves. The physical properties of this way obtained foam are shown in Table I.

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For comparison purposes, one uses a commercially available Polyether polyol and the fabrics of the formulation of Table I in the manner described in Section B of this example another cold-setting foam. The physical properties of this foam are also given in Table I.

The polyocyanate according to Table I has an NCO equivalent weight of about 105 and is a mixture of 50% by weight of one of 80% by weight 2,4-toluene diisocyanate and 20% by weight 2,6-toluene diisocyanate existing mixture and 50% by weight of a polymeric isocyanate with an NCO functionality of about 2.7 and an NCO equivalent weight of about 133.

Furthermore, in Table I, CP 4701A denotes the reaction product of glycerol and propylene oxide, which is in the end position Contains grafted ethylene oxide and an OH equivalent weight from 1545 has.

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TABLE I. Foraralienrog component

Polyisocyanate

ester-containing Polyätfeerp @ ly®I according to section A. of this example

CP 4701A

water

70% by weight solution v®ss in dipropylene glycol Physical properties Density (g / l)
Tensile strength (kg / c © ² ) elongation (%)

Entry strength (kg / 2 _s 5 cas (tear resistance)

90% stay

Sharah B foam C

set)

25% deflection mater pressure load

(compression load deflection) 65% deflection HBter module

DD

2 5

54 _S 4 I ₀ 43

9.76

0.34

, 3

0 _s 32

0.84 2 _n 47

25% DD

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Example 2

A. An ester modified polyol is made by 1 mol of the compound CP 3001 defined in the explanations for Examples 1 to 21 and 6 mol of maleic anhydride into a reaction vessel, which is equipped with a stirring device, with means for controlling the temperature, is equipped with an opening for the inlet of nitrogen and with means for vacuum control, the air removed by applying a vacuum to the reaction vessel for one hour, after releasing the vacuum with Nitrogen 30.0 mol of ethylene oxide is added, the contents of the reaction vessel are heated to 80 ° C. and it is 24 hours holds at this temperature. The temperature is then increased to 120 ° C. and held at this temperature for 15 hours. The volatile substances are removed by relaxing the pressure at 100 ° C., the reaction product is filtered and packaged it for storage. The ester-modified polyether polyol obtained has an OH content of 1.15% and an acid number of 0.15.

B. The first-containing polyether polyol obtained according to A is used and the substances according to the formulation contained in Table II in the manner described in Example 1-B a flexible polyurethane foam. The physical Properties of the foam are given in Table II.

C. For comparison purposes, make up a commercially available polyether polyol and the substances according to that contained in Table II Recipe a second flexible polyurethane foam in the manner described in Example 1-B. Even the physical properties of this foam are given in Table II.

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In the recipe according to Table II, the term "GP 3000" denotes a commercially available one with glycerol as the initiator manufactured polyoxypropylenetriol which has a hydroxyl equivalent weight of about 1000 has.

TABLE II Recipe

Component parts by weight

Foam B foam C

Mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate in a ratio

of 80:20% by weight 193 205

ester-containing polyether polyol,

manufactured according to section A 500

CP-3000A

water

Tetramethylbutandiamine

Siliconol

70% solution of bis (2-dimethylaminoethyl) ether in dipropylene glycol Tin (II) octoate

Physical Properties

Density (g / l)

Tensile strength (kg / cm ^)

Strain (%)

Tear resistance (kg / 2.5 cm)

permanent deformation (compression set) (90%)

25% deflection under pressure

(DD) (compression load deflection) (2.5 cm) 0.51 0.36

65% deflection under compressive load _£

(DD) (2.5 cm) 0.85 0.70

Module 65% DD 1.7 1.94

257oDD 2098 10/164 4

- 20th , 5 500 - 5.0 , 25 20th 0.75 I-l , 0. 1.75 1 , 25 25.4 1 0 0.68 25, 01 144 Ί, 0.36 211 125 8.7 1, 7th 7,

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Example 3

A. It is made from the ester-containing polyether polyol according to Example 1-A and the substances according to that contained in Table III Formulation a flexible polyurethane foam in the manner described in Example 1-B. The physical Properties of this foam are shown in Table III.

B. For comparison purposes, a commercially available polyether polyol and the substances according to the table III Containing formulation in the manner described in Example 1-B produced a second flexible polyurethane foam. Even the physical properties of this foam are shown in Table III.

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TABLE III Recipe

component

crude toluene diisocyanate (NCO equivalent weight 96)

ester-containing polyether polyol according to Example 1-A

CP 4701 (one defined in example 1-A Link)

water

70% solution of triethylenediamine in dipropylene glycol

Physical properties Property Density (g / l) Tensile strength (kg / cm ² ) Elongation (%) Tear strength (lg / 2.5 cm)

25% deflection under pressure load (DD) (2.5 cm)

65% bending under compression (DD) (2.5 cm)

Module, 65% DD 25% DD Foam A Foam B (parts by weight)

31.6

100.0

2.5

42.5

100.0

3.0 2.0

44.8 42.3 1.27 1.08 196 184 0.67 0.45 0.20 0.21 0.58 0.59 2.87 2.80

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Claims (1)

Claims; Process for producing a flexible polyurethane foam by mixing a polyisocyanate with a mixture from a «polyether polyol, a blowing agent and a catalyst, characterized in that the polyether polyol an ester-containing polyether polyol of the general formula If - ζ -f c - ο used, in which A is the remainder of an initiator with 2 to 4 active hydrogen atoms and one on active hydrogen based equivalent weight of about 400 to about 2500, Z the remainder of an internal anhydride of a saturated or unsaturated one acyclic aliphatic polycarboxylic acid, a saturated or unsaturated cyclic aliphatic Polycarboxylic acid, an aromatic polycarboxylic acid, a halogenated derivative of one of these acids or a mixture of these acids, one of R is hydrogen and the other R is hydrogen, an alkyl radical with 1 to 20 Designate carbon atoms, a phenyl radical, a phenoxymethyl radical or an alkoxymethyl radical and in the m an average value of 1.0 to 2.0, η the value 1 to 5, χ the value 2 to 4 and y the value 1 or 2. Process according to Claim 1, characterized in that A is the remainder of a product produced with glycerol as an initiator Polyoxyalkylene polyol and Z is the remainder of maleic anhydride. 209810/1644 - 17 - 2U2161 3. The method according to claim 1 or 2, characterized in that η has approximately the value 1. 4. The method according to claim 1 to 3, characterized in that χ has approximately the value 3. 5. The method according to claim 1 to 4, characterized in that the polyisocyanate used or toluene diisocyanate Is polymethylene polyphenyl isocyanate. 209810/1644